| 摘要 |
PROBLEM TO BE SOLVED: To stably detect a slip, even when two clocks being comparison objects are asynchronous. SOLUTION: A flip-flop circuit 2 samples a received clock S11 by a free- running clock S10, and an edge detection circuit 3 detects a leading edge of an output signal S12 of the flip-flop circuit 2. The free-running clock S10 and the received clock S11 operate two counter circuits 4, 5 respectively and two latch circuits 6, 7 latch maximum values of counts of the two counter circuits 4, 5. A discrimination circuit 8 compares the difference between the outputs of the latch circuits 6, 7 with a preset threshold (m). The discrimination circuit 8 discriminates detection of a slip, when the difference is in excess of the threshold value (m) and discriminates release of slip detection, when the difference is the threshold (m) or below so as to be able to detect a cycle slip even in an asynchronous state.
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